All foods were considered clean in the days of Noah, and that the only foods considered unclean were those that Israel was directed to avoid for the purposes of separating them from other nations.
Gen 9:3 Every moving thing that liveth shall be meat for you; even as the green herb have I given you all things.
Lev 20:24 But I have said unto you, Ye shall inherit their land, and I will give it unto you to possess it, a land that floweth with milk and honey: I [am] the LORD your God, which have separated you from [other] people. Lev 20:25 Ye shall therefore put difference between clean beasts and unclean, and between unclean fowls and clean: and ye shall not make your souls abominable by beast, or by fowl, or by any manner of living thing that creepeth on the ground, which I have separated from you as unclean. Lev 20:26 And ye shall be holy unto me: for I the LORD [am] holy, and have severed you from [other] people, that ye should be mine.
But Noah took on board seven of each the clean animals.